There is increasing recognition that a subset of women on welfare face multiple barriers to work and self-sufficiency. The consequences of welfare reform are likely to be extremely negative for the subpopulation of women heads-of-households with mental health and/or substance abuse related disorders. In particular, access to services by this at-risk population may be in jeopardy as a consequence of current welfare reforms. This begs a critical empirical question: How will the mental health service delivery system accommodate the needs of this at-risk population? Adequately understanding the forces affecting the utilization patterns of poor women using behavioral health services is critical for developing strategies to influence the utilization patterns of poor women using behavioral health services is critical for developing strategies to influence the impact of policy changes on access to services by this at risk population. This proposal deals with phase one of a study that will develop a longitudinal database and multivariate research methodology to examine changes to patterns of mental health and substance abuse care for the target population of poor women eligible for Medicaid based historically on receipt of Aid to Families with Dependent Children (AFDC), and now Temporary Assistance for Needy Families (TANF). The study will accomplish two interrelated objectives: (1) Provide an understanding of what factors explain the patterns of care of poor women heads-of-households receiving Medicaid mental health and substance abuse services; and (2) provide information to guide development of intervention strategies to improve access to and quality of mental health services for this at risk population, in the wake of major social welfare and health policy reformulation. This research fits into a larger, long term research agenda focused on providing information about both the impact of these policy reforms on the lives of women heads-of-households with mental health needs, and the mental health and larger human service system changes that must be undertaken to improve outcomes for this subset of the welfare population. Medicaid claims data will be combined with administrative data in an analysis of utilization patterns of the study population, including both system and service recipient characteristics. The following research questions will be addressed. 1. What are the patterns of care of this population (descriptive); and 2. What client and systems characteristics explain the patterns of care (explanatory)?